Composite material for use in the manufacture of electrical contacts and a method for its manufacture

ABSTRACT

An electrically conductive composite material for use in the manufacture of electrical contact components, consisting of a metal strip and a contact layer made of a silver or tin contact material, which contact layer is applied at least to one side of the metal strip, whereby the contact material contains as a first additive 0.5 to 60 weight percentage of carbon powder in the form of fine particles having a diameter of Ø 1 =5 to 200 nm and 0.5 to 60 weight percentage of a second powdery additive in the form of fine particles having a diameter of Ø 2 =5 to 200 nm. Moreover a device for the gas atomization of a jet of a flowable or liquid material and a method for the manufacture of an electrically conductive composite material and its use are disclosed.

FIELD OF THE INVENTION

[0001] The invention relates to an electrically conductive compositematerial for use in the manufacture of electrical contact componentsconsisting of a metal strip and a contact layer made of a silver or tincontact material, which contact layer is applied at least to one side ofthe metal strip. Moreover a device is provided for the gas atomizationof a jet of flowable or liquid material and a method for the manufactureof an electrically conductive composite material.

BACKGROUND OF THE INVENTION

[0002] Such electrical contact components are utilized, for example, asplug contacts in plug connectors or in plug-connector connections in theautomotive industry.

[0003] The design of the contact elements is of great importance for thereliability of plug connectors. The utilized contact carrier materialtogether with the utilized contact surface determines during operationthe aging behavior and the lifetime characteristics.

[0004] The known electrical contacts for this use consist usually of abase body (metal strip), in particular made of a Cu alloy, and a contactmaterial applied galvanically, via hot dip galvanizing (for example firetinning) or via roll bonding. In particular gold, silver or tin layersare used for this purpose. A powder-metallurgical manufacture of thecontact points, which are welded onto the contact area, is not possibleFor plug connectors, in particular the sleeve part, since the contactarea is being reshaped and thus is not freely accessible.

[0005] Thus a sufficient wear resistance and a low contact resistance ofthe plug connector system can be achieved during the planned lifetimeonly for operating voltages up to 14 Volt in view of the up to nowdemanded marginal conditions.

[0006] This, however, no longer applies when increased demands are madeof the plug contacts, for example, with respect to the possible dangerof the electric-arc formation in a 42 V electrical system in theautomotive industry, or with respect to the placing of the plug contactin the direct vicinity of the motor due to high temperatures. Theproblems of an electric-arc creation is already known in the case ofswitching contacts, for example in the case of relays. The specialcontact layers are in the case of switching contacts applied in anadditional operation through soldering or welding onto the carriermaterial. The contact material itself is manufactured in a precedingoperating step by sintering or extrusion.

[0007] This phenomena appears only at a voltage above 16 Volt in commonplug connections in the automotive field. The danger of the electric-arcformation and of the contact bouncing during plugging in or pulling outof the plug connector connections exists in a 42 V electrical system.The electric arc causes locally a heating up of the material to above1000° C., this leads to the contact surfaces of the plug connectorsbeing burnt off. It is also possible for incompletely pluggedconnections to cause through vibrations created during driving suchelectric arcs, which result in a crawling burning away and in the end atotal breakdown of a plug connection.

[0008] A material for electrical contacts made of silver and carbon isknown from the reference DE 195 03 184 C1. This reference deals with asinter material, which due to a certain carbon-black content has animproved burning characteristic. The carbon is for its manufacture addedin the form of carbon black with a primary particle size of less than150 nm silver, the mixture is isostatically cold pressed and thereaftersintered. With the same goal, namely to improve the burningcharacteristics and the welding resistance, a composite material forelectrical contacts is known from the reference DE 41 11 683 C2. Thecomposite material consists of silver or a silver alloy with a carboncontent, which is processed in the form of a combination of a carbonpowder and carbon fibers in a mass ratio of 10:1 to 1:10 with the metalcomponent.

[0009] The disadvantage of such materials is that their manufacture andfurther processing is not suited for the manufacture of electricalcontact components in connection with a reshaping of the metal strips.

[0010] Furthermore a device with an atomizer is known from the referenceEP 0 225 080 B1, with which device a jet of a liquid metal is atomizedwith a gas jet into a spray mist consisting of droplets. The atomizer isthereby supported tiltably about a stationary axis in such a manner thatthe spray mist is evenly distributed on a moving band-shaped substrateor another collecting device. The device is used for the manufacture ofthin metal strips or for coating of strips.

[0011] A surface-like even distribution of the applied metal layer isindeed achieved with this manufacturing method, however, it permitsfirst of all only a simple material selection with one melt component.Furthermore an atomizer movable relative to the metal jet represents anadditional apparatus expenditure.

SUMMARY OF THE INVENTION

[0012] The basic purpose of the invention is therefore to provide ametallic composite material, which is manufactured by means of a device,which is improved compared with the state of the art, and which alsomeets the increased demands mentioned above.

[0013] The purpose is attained, regarding the product, by anelectrically conductive composite material for the manufacture ofelectrical contact components, consisting of a metal strip and a contactlayer made out of a silver or tin contact material, which contact layeris applied at least to one side, whereby the contact material containsas the first additive 0.5 to 60 weight percentage of carbon powder inthe form of fine particles with a diameter ø₁=5 to 200 nm and 0.5 to 60weight percentage of a second powdery additive in the form of fineparticles with a diameter ø₂=5 to 200 nm.

[0014] The composite material of the invention is suited in particularfor plug connectors and plug-connector connections and also switchingcontacts.

[0015] The invention is thereby based on the premise that the compositematerial should have a plurality of characteristics which are optimallyadjusted to one another. For the selection of a suitable contactmaterial on a carrier material the following criteria or characteristicsshould among others be optimized:

[0016] Arc erosion resistance

[0017] high electrical/thermal conductivity

[0018] low needed contact force

[0019] abrasion/wear resistance

[0020] good working properties: solderable.

[0021] In particular the arc erosion resistance for use in 42 Velectrical systems in the automotive field should thereby be in theforeground in order to prevent a burning away of the contacts.

[0022] The electrically conductive composite material is for thispurpose provided with an additive of carbon. The electric arc createdduring the plugging in and pulling out of plug connectors and contactsproduces carbon compounds, through which an increase of the contactresistance through oxidation of the contact surfaces in the surroundingarea is essentially prevented.

[0023] Thus the main portion of the contact layer is a metal having analready good electrical conductivity, which forms the matrix into whichthe two additives are embedded and finely distributed corresponding totheir small diameter to form a homogeneous composite material. This hasalso a direct positive effect on further material characteristics. Inparticular, the finely distributed alloy components of varying hardnessand the therewith achieved homogenization opposes the wear of amechanically stressed surface.

[0024] The strips must be reshaped during the plug manufacture. Part ofa good workability involves the contact layer not coming loose from thecarrier during the reshaping. A preferred embodiment achieves an optimumby arranging an intermediate layer made of Ag or Sn with the thicknessD₃=0.1 to 1 μm between the metal strip and the contact layer. Theintermediate layer is thereby deposited onto a cleaned and activatedstrip surface.

[0025] The contact material contains in a preferred embodiment as thefirst additive 3 to 40 weight percentage of a carbon powder plate-likeand/or globularly and/or pearled in the form of fine particles having adiameter of ø₁=20 to 150 nm. Carbon has a decidedly low hardness incomparison to metallic materials. Especially for this reason it is ofimportance that the small particle size of this additive in thenanometer range leads to a composite material which has on its surface,due to metallic parts, a sufficient hardness and thus abrasionresistance against mechanical stress. The soft carbon powder is for thispurpose embedded in a harder metallic skeletal matrix.

[0026] In addition to a first additive, the second additive considersmaterials which improve the electrical conductivity, arc-erosionresistance, hardness and abrasion resistance. Thus also metallicparticles can be introduced. The second additive of a preferredembodiment has 2 to 50 weight percentage of a metal from the group Co,Cu, Mo, Ni, Ti, W in the form of fine particles having a diameter ofø₂=10 to 200 nm.

[0027] As an alternative hard particles can also be considered as thesecond additive. Advantageously these are 2 to 40 weight percentage of acarbide, preferably from the group SiC, Wc, in the form of fineparticles having a diameter of ø₂=10 to 200 nm.

[0028] As an alternative the second additive is advantageously 0.5 to 40weight percentage of a disulfide, preferably from the group MoS₂, WS₂,in the form of fine particles having a diameter of ø₂50 to 200 nm.

[0029] The second additive consists in a further alternative embodimentof 2 to 40 weight percentage of SnO₂ in the form of fine particleshaving a diameter of ø₂=5 to 100 nm.

[0030] The second additive is in a further alternative embodiment 2 to40 weight percentage of oxidical ceramic particles, preferably from thegroup Al₂O₃, ZrO₂, having a diameter of ø₂=50 to 150 nm.

[0031] Further advantageous, as the second additive, is 2 to 20 weightpercentage of PTFE (polytetrafluoro-ethylene) in the form of fineparticles having a diameter of ø₂=50 to 200 nm.

[0032] It is also of importance for the adhesiveness of the contactlayer on the carrier that, besides the electrical characteristics, areshaping is successful during the manufacture of the plug withoutremoving the contact layer. The thickness of the metal strip is for thispurpose in a preferred embodiment D₁=0.06 to 1.2 mm and the contactlayer D₂=0.5 to 10 μm. Suitable thickness ratios result from this, whichthickness ratios prevent a separating of the layers and also duringreshaping procedures.

[0033] For a suitable composite material it is also necessary to choosethe carriers accordingly. Preferred are thereby materials which have atleast a good up to a very good electrical conductivity. The metal stripconsists advantageously of Cu or a Cu alloy, of Fe or a Fe alloy, of Alor an Al alloy, of Ni or a Ni alloy.

[0034] The advantages achieved with the invention are, with respect tothe composite material in particular, that at high plug-in and pull-outspeeds either prevent the creation of an electric arc or if an electricarc is created same is immediately extinguished so that oxidation of thecontact surface will not result. In particular the intermediate layerguarantees an optimum adhesiveness of the contact layer on the carrier.Beyond already existing composite materials the inventive solutionoptimizes the characteristics of the composite material for use inelectrical engineering techniques.

[0035] The purpose is attained with respect to the device for the gasatomization of a jet of a flowable or liquid material, for example a jetof liquid metal or a metal alloy, with an atomizing system for theadmission of atomizing gas onto the jet for the atomization of the jetinto a spray mist consisting of droplets, whereby the atomizing systemis constructed annularly or elongated, and same has a continuous outletgap for the atomizing gas. Above the area of the atomizing system thereis arranged an injector for powder with a swirling chamber, whichinjector is connected to a solid material feed system.

[0036] The advantages achieved with the invention are with respect tothe device for the gas atomization that powder parts in the swirlingchamber are homogeneously moved into the spray mist. The high gas speedof the atomizing gas produces for this purpose in the area of theswirling chamber an underpressure which continuously effects adischarging of the powder particles from the chamber. The particlemovement in the swirling chamber dissolves the agglomeration of finepowder particles and thus takes care of a homogeneous distribution inthe separated layer. It is in particular possible to coat wider stripshaving an elongated form of the atomizing system without that thegas-atomizing device or its parts must be moved. The elongated part isfor this purpose aligned perpendicularly with respect to the directionof movement of the strip material.

[0037] A loading of the spray mist with powder particles places,depending on the condition of the powder, different demands on the typeof the admixture. The solid material feed system includes in a preferredembodiment a storage container for dry powder or a container for liquidsloaded with powder with supply lines. Thus it is already possible toreduce the agglomeration of the particles through the powderpreparation, in particular through a suspension in a suitable fluid.

[0038] The amount of material in the jet is advantageously controlled bya device having valve control and/or a device for the pressurization ofa melt storage container. With a suitable pressurization it is possibleto specifically control the material flow even without a valve since amelt flow can only be maintained with a suitable overpressure. Anadditional valve, however, permits yet shorter switching times to switchon and off the melt flow.

[0039] The purpose is attained, with respect to the method for themanufacture of a composite material with a device for the gasatomization, with the steps according to which a metal or a metal alloyis heated in a storage container above the melting point, the meltexists with pressurization in the form of a melt jet and is atomized bymeans of a flow of gas into a spray mist, is mixed with non-meltingadditives in particle form, and subsequently the atomized droplets aredeposited on a metal strip as a carrier material or a collecting device.

[0040] A cooling conveyor moving under the spray jet can serve as thecollecting device, from which cooling conveyor the spray product can bereleased.

[0041] The non-melting additives are fed in a preferred embodiment tothe melt flow from a swirling chamber.

[0042] This manufacturing method can work either in a continuousoperation or in a batch operation, where the strip to be coated issupplied either continuously or from a stack of superposed stripsections. The system is stored in a housing with an inlet and outletlock, which housing is flooded with nitrogen or a nitrogen/hydrogenmixture. A strip-cleaning and strip-activating station is positioned infront of the inlet lock, with which station the strip surface issuitably prepared prior to the coating for a good adhesiveness of thedeposited layer.

[0043] The atomization of the powder particles occurs in a preferredembodiment by using N₂. The additives are for this purpose blown intothe spray jet with a pressure of 0.15 to 1.5 MPa. The nitrogen entersdue to the overpressure with a very high pressure through an outlet gapinto a mixing chamber in order to swirl around the powder particlesintroduced into the mixing chamber and to obtain an optimum thoroughlyblended mixture. In addition, it is possible to effectively prevent anagglomeration of the nanopowder utilizing a sufficient gas speed, whichgas speed can also lie above the supersonic range. The pressurization ofthe powder components is for this purpose suitably controlled for anoptimum blending.

[0044] In order to be able to deposit in the manufacturing process theadditives in a variable combination, the additives are advantageouslyblown in independently from one another.

[0045] When choosing the depositing conditions, a uniform contact layerwith finely dispersed additives is desired. The metal strip is for thispurpose advantageously heated to a temperature of (0.6 to 0.9)×T_(s) ofthe contact material Sn or Ag. Thus it is possible to deposit suchlayers at the same time with a low porosity and high adhesion.

[0046] In order to improve the adhesiveness of the layer on the carriermaterial, the metal strip is, prior to the depositing of the layer,advantageously surface-treated with a fluxing agent for activation.

[0047] The layer thickness is adjusted through still other depositingparameters. The thickness D₂ of the contact layer is in a preferredembodiment for this purpose controlled by the spray jet density and therunning speed of the metal strip to be coated. The spray jet density ispreferably controlled by a needle valve or the like. When the needlevalve is thereby permanently open, then it is also possible for anall-over one-sided coating to occur. To create a uniform layer the metalstrip can be pulled through under the spray jet at a constant speed. Asan alternative, it is also possible to alone control without the valvedevice through a pressurization of the melt the material flow in thespray head.

[0048] By suitably choosing the depositing conditions it is possible toalso specifically adjust the porosity of the contact layer. An openporosity of the contact layer of 70 to 85% is adjusted in a particularlyadvantageous embodiment through the chosen spray parameters. The porouscontact layer is subsequently infiltrated with oil for self-lubrication.

[0049] Porous layers are aftertreated in a further method step byre-rolling the sprayed metal strip at a temperature of at least0.8×T_(s) of the layer matrix material in order to achieve a 100%thickness.

[0050] The metal strip is in a particularly preferred embodiment onlypartially coated. Thus it is possible to produce a partially resistivecoating, for example, at the tip of a plug.

[0051] In the case of partially resistive coatings the current iscontinuously reduced during the pulling process so that in dependency ofthe material and the voltage starting with a certain boundary resistancean electric arc can no longer form. The burning away characteristic isin this manner minimized in the case of such automatically shutting offcontacts.

[0052] For the manufacture of partially resistive coatings the metalstrip is advantageously covered with a mask. As an alternative it ispossible to shield the metal strip against the spray jet. The mask isfor this purpose not placed onto the carrier but is positioned at acertain distance in the jet.

[0053] Electronics in front means on the one hand increasedtemperatures, on the other hand an increased vibration stress. This isparticularly valid for multi-valve engineering. Current-conductingconnections like plug connectors, pressed-screen connections, relayconnections and wear and vibration resisting, high-temperature resistantcoatings are needed for use in the automotive field. The electricallyconductive composite material finds in this manner use in the automotivefield and in particular in electric contact components like plugconnectors and plug-connector connections.

[0054] The advantages achieved with the invention consist, with respectto the method in particular, in the contact coating of a metal stripbeing partially applied as a carrier material in order to manufactureautomatically switching-off contacts with little burning away behavior.In particular a contact layer is produced on a carrier material duringone operating sequence through a suitable parameter selection, whichcontact layer can be further processed directly as strip material.Beyond already existing manufacturing methods it is thus possible toinclude the coating process easily in a rational series production.

BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Exemplary embodiments of the invention will be discussed ingreater detail in connection with the drawings, in which:

[0056]FIG. 1 illustrates a composite material having a carrier and acontact layer, and

[0057]FIG. 2 is a schematic illustration of the gas-atomizing device.

DETAILED DESCRIPTION

[0058] Corresponding parts have been identified with the same referencenumerals in all figures.

[0059] The composite material 1 for the manufacture of electricalcontact components consists of a metal strip 2 as the carrier made ofmetal and a contact layer 4 made of a silver or tin contact material,which contact layer is applied at least to one side thereof. The contactmaterial contains as the first additive 0.5 to 60 weight percentage ofcarbon powder in the form of fine particles having a diameter of ø₁=5 to200 nm and 0.5 to 60 weight percentage of a second powdery additive ofvarying materials in the form of fine particles with a diameter of ø₂=5to 200 nm. An intermediate layer 6 made of Ag or Sn having a thicknessD₃=0.1 to 1 μm is arranged between the metal strip 2 and contact layer4. The thickness of the metal strip 2 is preferably D₁=0.06 to 1.2 mmand of the contact layer 4 D₂=0.5 to 10 μm. The metal strip 2 issurface-treated with a fluxing agent for activation.

[0060] The gas-atomizing device 10 schematically illustrated in FIG. 2houses a melt container 12, which is arranged in a heated housing 40 andhas filler necks and feed channels 14 for feeding the melt to a nozzle28. A needle valve mechanism 18 is provided from which the jet of liquidmetal or a metal alloy exits. The exiting amount is controlled by aconnection 16 which subjects the chamber 12 to pressurization, whichconnection is mounted on the melt container 12. The filler neck on themelt container 12, to facilitate a pressurization thereof, is closed offgastight with a plug or a screw connection.

[0061] A container 20 is in addition arranged in the heated housing 40,which container has filler necks for liquids and mixtures made of aliquid loaded with powder. The container 20 is connected via feedchannels 22 to the injector system 32 having a swirling chamber 26,which injector system 32 encircles the needle valve 18. The exitingamount from the container 20 is also controlled by a connection 24mounted on the container 20 to subject the chamber 20 to pressurization.As an alternative or in addition, there exists the possibility toconnect further solid material feed systems having a powder receptacle44 for dry powder to the heated housing 40, which systems are connectedto the injector system 32 via channels not shown in the schematicillustration. Further melt receptacles, if necessary with a separateheating system, can be docked to a connecting system 42.

[0062] The melt exiting through the needle valve 18 is mixed with thesolid materials from the swirling chamber 26 and is loaded withatomizing gas from a N₂ atomizing system 34 so that from the jet iscreated a spray mist consisting of droplets, which spray mist isdeposited on a strip 2. A N₂ chamber 36, directly in front of the N₂outlet gap 38, assures a constant gas supply.

[0063] An outlet funnel 30 having a specified outlet cone shape, whichguarantees a deposit over the entire strip width, is used to guide thespray jet.

[0064] A mask 8 is positioned in the path of the jet spray or on thesubstrate to facilitate a selective depositing.

[0065] The atomizing system 34 can be of an annular configuration orelongated into the image plane of FIG. 2, whereby same has a continuousoutlet gap 38 for the N₂ atomizing gas. The metal strip 2 is pretreatedon the surfaces with flow medium for activation by the cleaning andactivating system 48. The strip can be coated in a continuous operationor in the form of a stacked array 46 in a batch operation.

List of Reference Numerals

[0066]1 Composite material

[0067]2 metal band

[0068]4 contact layer

[0069]6 intermediate layer

[0070]8 mask

[0071]10 gas-atomizing device

[0072]12 melt container

[0073]14 feed channels for melt

[0074]16 connection for pressurization

[0075]18 needle valve

[0076]20 container for liquids and mixtures

[0077]22 feed channels

[0078]24 connection for pressurization

[0079]26 swirling chamber

[0080]28 nozzle

[0081]30 outlet funnel/spray jet guide

[0082]32 injector system with swirl chamber

[0083]34 N₂ atomizing system

[0084]36 N₂ chamber

[0085]38 N₂ outlet gap

[0086]40 heated housing

[0087]42 connection for a further melt receptacle

[0088]44 powder receptacle

[0089]46 stacked position for batch operation

[0090]48 cleaning and activating system

What is claimed is:
 1. An electrically conductive composite material foruse in the manufacture of electrical contact components, in particularof plug connectors, plug-connector connections, consisting of a metalstrip and a contact layer made of a silver or tin contact material,which contact layer is applied at least to one side, wherein the contactmaterial contains as the first additive 0.5 to 60 weight percentage ofcarbon powder in the form of fine particles having a diameter of ø₁=5 to200 nm and 0.5 to 60 weight percentage of a second powdery additive inthe form of fine particles for improving the electrical conductivity,hardness and abrasion resistance and having a diameter of ø₂=5 to 200nm.
 2. The composite material according to claim 1, wherein anintermediate layer made of Ag or Sn with a thickness D₃=0.1 to 1 μm isarranged between the metal strip and the contact layer.
 3. The compositematerial according to claim 1, wherein the contact material contains asthe first additive 3 to 40 weight percentage of a carbon powderplate-like and/or globularly and/or pearled in the form of fineparticles having a diameter of ø₁=20 to 150 nm.
 4. The compositematerial according to claim 1, wherein the second additive is 2 to 50weight percentage of a metal from the group Co, Cu, Mo, Ni, Ti, W in theform of the fine particles having a diameter of ø₂=10 to 200 nm.
 5. Thecomposite material according to claim 1, wherein the second additive is2 to 40 weight percentage of a carbide in the form of small particleshaving a diameter of ø₂=10 to 200 nm.
 6. The composite materialaccording to claim 1, wherein the second additive is 0.5 to 40 weightpercentage of a disulfide from the group MOS₂, WS₂, in the form of smallparticles having a diameter of ø₂=50 to 200 nm.
 7. The compositematerial according to claim 1, wherein the second additive is 2 to 40weight percentage of a SnO₂ in the form of small particles having adiameter of ø₂=5 to 100 nm.
 8. The composite material according to claim1, wherein the second additive is 2 to 40 weight percentage of oxidicceramic particles from the group Al₂O₃, ZrO₂, having a diameter of ø₂=50to 150 nm.
 9. The composite material according to claim 1, wherein thesecond additive is 2 to 20 weight percentage of PTFE in the form of fineparticles having a diameter of ø₂=50 to 200 nm.
 10. The compositematerial according to claim 1, wherein the thickness of the metal stripis D₁=0.06 to 1.2 mm and of the contact layer D₂=0.5 to 10 μm.
 11. Thecomposite material according to claim 1, wherein the metal stripconsists of Cu or a Cu alloy, of Fe or a Fe alloy, of Al or an Al alloy,of Ni or a Ni alloy.
 12. A device for the gas atomization of a jet of aflowable or liquid material utilizing an atomizing system for the supplyof atomizing gas onto the jet for the atomization of the jet into aspray mist consisting of droplets, wherein the atomizing system isannularly configured or elongated, whereby same has a continuous outletgap for the atomizing gas, and above the area of the atomizing systemthere is arranged an injector system for powder and having a swirlingchamber connected to a solid material feed system.
 13. The device forthe gas atomization according to claim 12, wherein the solid materialfeed system includes a storage container for dry powder or a containerfor liquids supplied with powder through supply lines.
 14. The devicefor the gas atomization according to claim 12, wherein the materialamount of the jet is controlled by a device having a valve controland/or a device for the pressurization of a melt storage container. 15.A method for the manufacture of a composite material according to claim1, utilizing a gas atomization device, comprising the steps, heating ametal or a metal alloy in a storage container above the melting point,pressurizing the liquid melt to cause it to exit through a nozzle in theform of a melt jet and be atomized by means of a gas flow into a spraymist, be mixed with non-melting additives in particle form, andsubsequently causing atomized droplets to be deposited on a metal stripas carrier material or a collecting device.
 16. The method for themanufacture of a composite material according to claim 15, wherein thenon-melting additives are fed to the melt flow from a swirling chamber.17. The method according to claim 15, wherein the atomization occurswith the use of N₂ or a N₂/H₂ mixture.
 18. The method according to claim15, wherein a blowing of the additives into the spray jet occurs at apressure of 0.15 to 1.5 Mpa.
 19. The method according to claim 15,wherein a blowing in of the additives occurs independently from oneanother.
 20. The method according to claim 15, wherein the metal stripis heated to a temperature of (0.6 to 0.9)×T_(s) of the contactmaterial.
 21. The method according to claim 15, wherein the metal stripis surface-treated with a fluxing agent for activation.
 22. The methodaccording to claim 15, wherein the thickness D₂ of the contact layer iscontrolled by the spray jet density and the running speed of the metalstrip to be coated.
 23. The method according to claim 22, wherein thespray jet density is controlled by a needle valve or the like.
 24. Themethod according to claim 15, wherein the metal strip is pulled throughunder the spray jet at a constant speed.
 25. The method according toclaim 15, wherein an open porosity of the contact layer of 70 to 85% isadjusted through the chosen spray parameters.
 26. The method accordingto claim 25, wherein the porous contact layer is infiltrated with oil.27. The method according to claim 15, wherein the sprayed metal strip isre-rolled at a temperature of at least 0.8×T_(s) of the metal bandmaterial in order to achieve a 100% density.
 28. The method according toclaim 15, wherein the metal strip is only partially coated.
 29. Themethod according to claim 28, wherein the metal strip is covered with amask.
 30. The method according to claim 28, wherein the metal strip isprotected against the spray jet.
 31. Electrical contact components foruse in the automotive field, namely plug connectors and plug-connectorconnections, made according to the process of claim 15.